Cracked brake disc
Discussion
I drove the car to work as usual yesterday morning with no issues, but when I fired it up at lunch time to nip down to the sandwich pie shop I noticed a horrible judder from the steering wheel and brake pedal while braking. Took it to my local mechanic and he spotted the problem:
Thankfully Walkinshaw were able to send me out a new set of discs and pads for Saturday morning arrival and I got them fitted this afternoon.
You can clearly see the many micro fractures on the disc surface as well as the big one. These micro cracks I've had many times before on the old VXR8 after throwing it around a track and I've never really been worried by them, but the grand canyon is a new one on me.
The cracked disc was on the car from new and had done just under 20k including a single track day about a month a go. Perhaps I need a bigger brake kit...
Thankfully Walkinshaw were able to send me out a new set of discs and pads for Saturday morning arrival and I got them fitted this afternoon.
You can clearly see the many micro fractures on the disc surface as well as the big one. These micro cracks I've had many times before on the old VXR8 after throwing it around a track and I've never really been worried by them, but the grand canyon is a new one on me.
The cracked disc was on the car from new and had done just under 20k including a single track day about a month a go. Perhaps I need a bigger brake kit...
thats a nice crack 
Any disc can crack, there would probably have been some warning cracks before the big one opened up...but lets face it, how often does anyone really inspect their discs.
Big heavy car, standard or replacement discs, potentially made worse with uprated pads.
They'll never last forever, especially if they see some hard braking, and definitely track use.
Time for an upgrade.
Big heavy car, standard or replacement discs, potentially made worse with uprated pads.
They'll never last forever, especially if they see some hard braking, and definitely track use.
Time for an upgrade.
Gary H 2008 said:
And what would you suggest?
A proper racing disc. AP, Alcon PF etcThere is no guarantee they'll never crack either, but they would be far more resilient.
They'd be made from better materials from the outset to withstand the heat cycles.
If you're looking for a cheap solution, that'll be a lot harder.
Cheapest compromise solution would be to get some proper disc/bells made to suit your existing calipers
stevieturbo said:
A proper racing disc. AP, Alcon PF etc
There is no guarantee they'll never crack either, but they would be far more resilient.
They'd be made from better materials from the outset to withstand the heat cycles.
If you're looking for a cheap solution, that'll be a lot harder.
Cheapest compromise solution would be to get some proper disc/bells made to suit your existing calipers
Interesting - as I said, I've had no problems with the dba 2-piece, and as you pointed out these are heavy, heavy cars.There is no guarantee they'll never crack either, but they would be far more resilient.
They'd be made from better materials from the outset to withstand the heat cycles.
If you're looking for a cheap solution, that'll be a lot harder.
Cheapest compromise solution would be to get some proper disc/bells made to suit your existing calipers
pah250 said:
stigmundfreud said:
Buy a BMW
The day that BMW make and sell a BMW that sounds like my VXR8, I'll consider it, until then...
Bring back the shark nose and a sound track that isn't piped into the cabin via the speakers and I might return some day
Gary H 2008 said:
Been running the Dba 2-piece up front now with Pagid RS29's for over a year and 11K miles with no issues. Pads are half worn and there are micro cracks appearing, but nothing to be concerned about until I change them in a few months
Have you done many track days since you put these on? If so how do you find they stand up to track conditions?I find the standard brakes to be perfectly satisfactory on the track provided braided hoses are fitted (apart from the cracked discs of course!)
chrisgixer said:
pah250 said:
chrisgixer said:
Are the cracked discs, worn beyond then minimum thickness limit?
No, not even closeBut that said, who knows, may be I did do it once and that might have been enough to get the crack going. I'll never know for sure.
Micro cracked a brand new set of front AP discs at TR last year 
That's what you get repeatedly abusing the brakes from stone cold to red hot. I didn't help matters by the way I was applying the brakes but how often do you get to try out max brake effort at 160+ legally and safely? Was a price worth playing if I'm honest.
Have to say they never developed large cracks like above
That's what you get repeatedly abusing the brakes from stone cold to red hot. I didn't help matters by the way I was applying the brakes but how often do you get to try out max brake effort at 160+ legally and safely? Was a price worth playing if I'm honest.
Have to say they never developed large cracks like above
EmmaJ said:
Micro cracked a brand new set of front AP discs at TR last year
That's what you get repeatedly abusing the brakes from stone cold to red hot. I didn't help matters by the way I was applying the brakes but how often do you get to try out max brake effort at 160+ legally and safely? Was a price worth playing if I'm honest.
Have to say they never developed large cracks like above
Small cracks arent really an issue. They happen, but it can take a very long time for them to develop into anything that will cause concern...and that may never happen.That's what you get repeatedly abusing the brakes from stone cold to red hot. I didn't help matters by the way I was applying the brakes but how often do you get to try out max brake effort at 160+ legally and safely? Was a price worth playing if I'm honest.
Have to say they never developed large cracks like above
But as those racing discs will be made from more suitable materials from the outset, they will withstand the heat cycles better, so far less chance of total failure as happened with the pictured discs.
But lets face it...brake discs take one hell of a hammering !
Not always visible during the daytime, but in darkness, it really isnt that difficult to get some discs glowing very bright red. They do it in daylight too...you just dont see it the same.
Edited by stevieturbo on Sunday 13th July 09:17
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